Method and apparatus for switching several electric circuits

ABSTRACT

The invention relates to a method for switching several electric circuits in a vehicle, wherein several positions of an actuating element are binarily coded, the binary codification is fed to a logic and the logic controls the switching of the electric circuits, and also a corresponding switch with an actuating element and a switching device for attaining several switching modes, depending upon the position of the actuating element, wherein the switching device is constructed of several switching elements with two switching modes each, so that there results a binary codification of the switching modes of all switching elements, depending upon the position of the actuating element in order to switch the electric circuits by means of a logic.

BACKGROUND OF THE INVENTION

The invention relates to a method and apparatus for switching severalelectric circuits, particularly, circuit of a motor vehicle.

Such switching methods and switches are used in vehicle interiors forthe control of a plurality of electric circuits and their associatedelectrically driven devices in the electrical system of the motorvehicle.

With conventional switching methods, switching contacts of amulti-position switch are directly electrically connected with theelectric circuits to be switched.

Thus, the different illumination modes—parking lights, driving lights,fog lights, rear fog lights, high beams, and the like—are typicallyswitched directly via a single multi-position switch.

Because of the high power drawn by certain electrically driven devices,for example the driving lights, it is necessary that the switchingcontacts for switching high power or high current in a traditionaltwelve volt wiring system be designed to inhibit wear and tear that candegrade functionality.

As a result of the necessary use of wear and tear inhibiting contactsfor the switching of high power outputs, the cost of manufacturing suchswitches is high.

Therefore, it is an object of the present invention to provide a lowcost and easily produced method and apparatus for the switching ofseveral electric circuits of a vehicle.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, control ofthe electric circuits of the electrical devices is not effectuateddirectly, but rather indirectly by means of binary codification of thepositions of an actuation element by means of switching elements, e.g.micro-switches, which are not required to switch high output power.

The binary coding permits utilization of cost-effective logic modules,such as gate or processor logic, which in turn controls the electriccircuits via known, low-loss, cost-effective electrical switching and orcontrol elements such as thyristors, triacs and the like.

As a result, the use of cost-effective switches for low output power ismade possible. In addition, due to the binary codification standard,cost-effective, mass-produced components can be used in the switch for avast range of applications, inasmuch as the specific switching functionsof the electric circuits are determined by the logic. Such logic mayincludes, for example, a gate or logic arrays, possibly programmablelogic arrays, or processor logic.

These logic modules are selectively arranged at or in the switch asdesired, at least during the manufacturing process, so that they can beeasily exchanged.

It is, however, also contemplated that the binary codification of theswitch and/or the position of its actuating element are fed via a bussystem to a central logic, e.g. an on-board computer, which is alsoresponsible for the control of additional electronic functions.

In accordance with another aspect of the present invention, the numberof the coding possibilities is greater than the number of the positionsof the actuating element or the desired switching modes. The redundantcodification possibilities can be employed for a redundancy verificationof the positions of the actuating element, or for verifying a particularswitching functions.

For example, a switching element serving as a redundancy switch isadditionally activated by the actuating element via a profile disk inthe position of a certain mode (e.g., “0” or “1” position) to which thecertain mode, which is codified, such as “driving light on” has alreadybeen switched on via the other switching elements. The dual activationof a certain switching function is linked by a logical OR-gate, so thatonly one activation suffices—i.e. either the redundancy switch or theother (codified) switches—for switching on the given mode, e.g. theexemplary “driving light on” mode.

It is thereby possible to ensure that a safety-related function orfeature such as “driving light on” operates properly despite a switchmalfunction due to the redundancy. It is, of course, also possible toemploy other redundancy principles as desired, rather than the describedredundancy switch.

For example, it is possible to actuate the switch elements ormicro-scanners via the profile disks in such a manner that eachcodification combination is distinguished by at least two bits from aneighboring combination (e.g., 0000, 0011, 0101, 1000, etc.) or even arandomly chosen combination. The randomly allowed combination or changeis then be by a logic circuit which, in case of a dual redundancy,selectively correctively intervene and/or trigger an alarm.

Additional benefits and advantages of the present invention will becomeapparent to those of ordinary skill in the art upon reading andunderstanding the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take form in various components and arrangements ofcomponents, and in various steps and arrangements of steps. The drawingsare only for the purpose of illustrating preferred embodiments and arenot to be construed as limiting the invention.

FIG. 1 shows a perspective view of a rotational light switch inaccordance a first embodiment of the invention;

FIG. 2 shows an enlarged view of the lower section of the turning lightswitch of FIG. 1;

FIG. 3 shows a top view of a bottom plate of a rotational light switchin accordance with anther embodiment of the invention;

FIG. 4 shows a perspective view of the bottom plate of FIG. 3; and

FIG. 5 shows a schematic representation of the switching positions of athe subject light switch.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, the turning light switch 1 includes a knob 3disposed on its upper side, which can be manually operated by a user.The knob 3 is rigidly affixed, in detachable fashion, on the end of ashaft 5 that protrudes from a housing 2.

The shaft 5 swivels or turns and is also longitudinally displaceablewith respect to the upper- and under-side of the housing 2. A bottomplate 9 is arranged in stationary fashion in a middle region of theinside of the housing 2. The shaft 5 extends vertically through acentral opening in the bottom plate 9. The opening is larger than theouter dimensions of the shaft segment that passes therethrough. Aprofile disk 7 is arranged on the shaft 5 below the bottom plate 9 in atwist-proof and longitudinally displaceable fashion. To effectuate thetwist-proof and longitudinally displaceable arrangement of the profiledisk 7 on the shaft 5 the profile disk 7 includes a centralhexagonally-shaped opening that receives a segment of the shaft 5 thathas a hexagonal outer exterior. The hexagonally-shaped opening hascorresponding or slightly larger dimensions relative to thehexagonally-shaped shaft segment.

Below the profile disk 7, the shaft 5 passes through a pivot casing 8comprising a hollow cylindrical body that is arranged in stationaryfashion in the housing 1 or disposed on the underside of the housing 1.The shaft 5 swivels or turns and is longitudinally displaceable withinthe pivot casing 8. The upper or front side of the casing 8 provides alower fixed limiting stop for the underside of the profile disk 7. Theupper side of the profile disk 7 impinges upon the contacts of aplurality of micro-switches 11, 12, 13, 14, or impinges upon themicro-switches 11, 12, 13, 14 by means of a spring force. As a result,the profile disk 7 is fixedly positioned in the longitudinal directionin the housing, in spite of the longitudinal displaceability of theshaft 5. In order to precisely position of the profile disk 7, it isalso contemplated that the profile disk 7 be arranged at the casing 8 ina rotatable but longitudinally stationary fashion by means of a bayonetcatch (not shown).

The shaft 5 is limited against removal by an operator pulling on theknob 3 by means of recesses and projections (not shown) on the shaft 5and elements cooperating with the same which are fixedly arranged on thehousing 2.

Conversely, the shaft 5 can be inserted only to the point where theunderside of the knob 3 rests against the exterior of the upper side ofthe housing 2.

In this fashion, the shaft 5 can be pulled-out or pushed-in withindefined longitudinal limits without longitudinally displacing theprofile disk 7.

With reference next to FIG. 2, the profile disk 7 includes a profileconsisting of projections and recesses disposed on an upper side of theprofile disk 7 and facing the bottom plate 9. The projections andrecesses comprising the profile effectuate selective actuation of themicro-switches 11, 12, 13, 14.

For that purpose, the micro-switches 11, 12, 13, 14 can be arrangedtangentially, as shown in FIGS. 1 and 2, or the micro-switches 11, 12,13, 14 can be arranged in a radial direction, as shown in FIGS. 3 and 4.The configuration of the micro-switches 11, 12, 13, 14 cooperates withthe arrangement of the profile of the profile disk 7 to effectuate thedesired switching characteristics of the micro-switches 11, 12, 13, 14.

By appropriate cooperation between the surface profile of the profiledisk 7 and the spring-mounted contacts of the micro-switches 11, 12, 13,14 it is possible, for example, to effectuate a switching characteristicas shown in the Table below:

Position of Switch Switch Switch Switch Turning Knob Function 11 12 1314 I Parking Light 1 0 1 1 Left II Parking Light 1 1 0 1 Right IIIAutomatic 1 0 0 1 Driving Light IV Light Off 0 0 0 1 V Stationary Light0 1 0 1 VI Driving Light 0 1 1 0

With reference to FIG. 5, knob positions I through VI are representedschematically. These knob positions correspond to the position orcombination of the micro-switches 11, 12, 13, 14 shown in the Table. Inthe exemplary binary codification of the switch positions shown above,the switch 14 acts as a redundancy switch, which contributes towardguaranteeing a particularly important function, e.g. the driving lightor the dimmer light against malfunction.

The function “driving light” is effectuated, in addition to thecodification via the switches 11, 12, 13, by means of a “0” position(i.e., driving light active) of switch 14. The “0” position effectuating“driving light active” in the exemplary case corresponds to the mode“switch not activated” or “no current” or “conductance to ground”, sothat the driving light remains turned on via a logic switch by means ofa logical “OR” linkage of the switch 14 with the 3-bit codecorresponding to “driving light active”, which in the Table correspondsto the switches 11, 12, 13 taking the values 011. A potentialmalfunction is thereby recognized as such and can even be indicated by a“malfunction” warning indicator. This has the advantage that amalfunction, such as a ground short circuit of one or more of theswitches 11, 12, 13 (for example if, in addition, the fog light isturned on or off) will not lead to an unintended and dangerousswitching-off of the driving lights.

Therefore, it is also contemplated that the redundancy function of theredundancy switch is realized in the “1” position instead of the “0”position. This permits recognition of the malfunction “short circuit”instead of “ground short circuit”, since in the case of a short circuitthe corresponding line is drawn to a “1” electrical potential.

The redundancy switches can, of course, be employed in combination withone another as desired, so that both malfunctions can be detected and/orswitched to a permissible fault mode.

Needless to say, the binary codification of the switch positions of amulti-function switch is not limited to a 3-bit codification with anadditional redundancy switch. Rather, any desired number of switchpositions can be realized as a multi-bit code with one or severalredundancy switches. As an example, redundancy switches can beselectively used for several safety-relevant switching functions.

The switching method according to an aspect of the invention enablescost-effective, simple construction of a switch with binary codificationby means of micro-switches with low power output and optionalredundancy. Instead of effectuating the redundancy as described, it isalso contemplated to realize the redundancy by special codificationstages. For example, redundancy can be built-in by changing at least twomodes per stage, or by having redundancy for sums of digits, etc.

Control of the electric circuits is effectuated via control electronics,e.g. a logic unit and a switching unit, which are arranged in or at theswitch 1, either in part or totally as desired. The control electronicsare adapted for incorporation into a central controller, such as forexample an on-board computer.

With reference to FIGS. 3 and 4, in addition to the micro-switches 11,12, 13, 14 additional micro-switches 15, 16 are provided on the bottomplate 9. The micro-switches 15, 16 are preferably oriented radiallyinward toward the shaft 5 rather than toward the profile disk 7 as theswitches 11, 12, 13, 14. The switches 15, 16 are thus actuated by meansof appropriate recesses and projections on the surface of the shaft 5.This is done, for example, by a rotation or by longitudinal displacementof the shaft 5. In the embodiment of FIGS. 3 and 4, the switches 15, 16serve for detection of a two-stage pull-out or push-in of the shaft 5which actuates corresponding switching functions, such as fog lightsand/or rear fog lights in the described example application.

In order to ensure convenient operation of the switch 1, catch indicesor catch elements (not shown) are arranged in the switch 1. Theseindices or elements ensure mechanical latching at selected rotationaland longitudinal positions of the switch 1. Such catch elements or catchindices are well known to those of ordinary skill in the art and neednot be illustrated herein for an enabling disclosure of the invention.

The invention has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations insofar as they come within thescope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A method for switching electric circuits,comprising: binarily encoding a plurality of positions of an actuatingelement, at least one of said plurality of positions of the actuatingelement having a redundant encoding; transmitting the binary encodingand redundant encoding to a logic unit; and switching the electriccircuits based upon an output of the logic unit.
 2. The method accordingto claim 1, wherein the transmitting of the binary codification to alogic unit includes transmitting the binary codification to said logicunit via a bus system.
 3. The method according to claim 1, furthercomprising: controlling additional electrical functions based uponadditional outputs of the logic unit.
 4. The method according to claim1, further comprising: verifying that the binary codificationcorresponds to a valid position of the actuating element.
 5. The methodaccording to claim 4, wherein the verifying includes: comparing thebinary codification against a subset of binary combinations, said subsetincluding the binary combinations that correspond to positions of theactuating element, the number of combinations comprising said subsetbeing less than 2^(n) where n is the number of binary bits.
 6. A switchfor selectively switching a plurality of associated electric circuits,the switch comprising: an actuating element having a plurality ofselectable positions; a plurality of binary switching elements, eachbinary switching element defining a binary bit value based on theposition of the actuating element; a binary codification defined by thebinary bit values of the plurality of switching elements; a logic unitadapted to receive the binary codification and selectively switch theplurality of associated electric circuits based on the binarycodification; a redundancy binary switching element defining aredundancy binary value; and a logical “OR” element in communicationwith the logic unit and defining a relationship between the binarycodification and the redundancy binary value to protect at least oneswitch Position independent of the binary bit values of the plurality ofbinary switching elements.
 7. The switch as set forth in claim 6,wherein the plurality of binary switching elements further include aplurality of low-power micro-switches.
 8. The switch as set forth inclaim 6, wherein the actuating element further includes: a knob; a shaftoperatively connected with the knob; and a profile disk, operativelyconnected with the shaft, the profile disk being cooperative with theplurality of binary switching elements to select the binary bit valuesdefined by the binary switching elements.
 9. The switch as set forth inclaim 8, wherein the actuating element further includes: a twist-proofand longitudinally displaceable operative connection between the shaftand the profile disk.
 10. The switch as set forth in claim 6, whereinthe logic unit further includes: one of an electronic controller and anon-board computer.
 11. A vehicle lighting controller for selectivelyapplying electrical power to a plurality of lighting systems of avehicle, said plurality of lighting systems including a driving lightssystem, the vehicle lighting controller comprising: an actuating elementhaving a plurality of manually selectable positions; a plurality oflow-power binary switches communicating with the actuating element todefine an ordered combination of bits corresponding to the actuatingelement position; an electronic controller that receives the orderedcombination of bits and effectuates application of electrical power toselected lighting systems based on the ordered combination of bits; atleast one redundancy element that acquires a fault value conditionalupon one of an electrical short and an electrical ground short occurringin the vehicle lighting controller; and a safety element thateffectuates application of electrical sower to the driving lights systemconditional upon the at least one redundancy element acquiring the faultvalue independent of a logical condition of said ordered combination ofbits.
 12. The vehicle lighting controller as set forth in claim 11,wherein the at least one redundancy element further includes a low powerbinary switch.
 13. The vehicle lighting controller as set forth in claim11, wherein the electronic controller further includes an on-boardcomputer.
 14. The vehicle lighting controller as set forth in claim 11,wherein the actuating element further includes: a knob; a shaftconnected with the knob; and a profile disk operatively connected withthe shaft and having a plurality of selectable orientations relative tothe switches, the orientations corresponding to the plurality ofmanually selectable positions of the actuating element, the profile diskfurther having a surface profile that selectively operates the pluralityof low-power switches to effectuate definition of the orderedcombination of bits.
 15. The vehicle lighting controller as set forth inclaim 14, wherein the actuating element further includes: a housinginside which the shaft is mounted in a swivelable and axiallytranslatable fashion.
 16. The vehicle lighting controller as set forthin claim 15, wherein the plurality of manually selectable positions ofthe actuating element include: a plurality of manually selectablepositions of the shaft, wherein each of the plurality of shaft positionsis defined by a swivel position and an axial translation position.
 17. Amethod for switching a plurality of lighting circuits of a vehiclecomprising: binary-coding a plurality of positions of an activationelement; delivering the binary coding to a logic device, the logicdevice controlling the switching of the circuits; and, predominantlyprotecting at least one position of the activation element and as aresult of a malfunction is detected.
 18. The method according to claim17 wherein the coding is read out from the logic device via a bussystem.
 19. The method according to claim 18 wherein the logic device isembodied as a central logic device for controlling further electricalfunctions and their respective circuits.
 20. A light switch for avehicle comprising: an activation element and a switching device forbringing about a plurality of switched states as a function of theposition of the activation element the switching device including aplurality of switching elements with two switched states each so that abinary coding of the switched states of all the switching elementsresults as a function of the position of the activation element in orderto switch the circuits by means of a logic device, the switching devicehaving at least one further switching element for at least one positionof the activation element in order to protect at least one positionindependently of the switched states of the other switching elements.21. The switch according to claim 20 wherein the switching elementsinclude low power microswitches.
 22. The switch according to claim 21wherein the activation element includes as a rotary knob which isconnected via an axle to a profiled disk for activating the switchingelement.
 23. The switch according to claim 22 wherein the profiled diskis mounted on the axle so as to be fixed in terms of rotation andcapable of displacement in the longitudinal direction so that the rotaryknob can be pulled out and pushed its axis of rotation in order toactivate further switching elements.